Cylindrical gear is widely used in high-speed and heavy-duty occasions because of its compact structure, strong bearing capacity and stable transmission ratio. In order to improve the transmission accuracy and prolong the service life, chamfering is a common process means. The chamfered cylindrical gear can avoid burr due to collision and reduce the impact of gear noise.
At present, the main types of processes used are grinding method and extrusion method. The grinding method adopts the grinding method to chamfer, which has the problems of low machining efficiency and difficult to control the grinding shape; The edge extruding method uses the edge extruding cutter to engage with the gear to be processed without backlash to chamfer the whole gear profile completely and evenly, but the chamfering process will produce a large number of flash, and the tool design is also more complex. With the increasing requirements of gear processing performance, the research on chamfering principle and the development of chamfering tools are becoming more and more important.
Therefore, scholars at home and abroad have done a lot of research. Han Weina et al. [5] studied the chamfering method of the top line of the large gear of the spiral bevel gear pair based on the machining principle of the semi hobbing method, and chamfered the inner and outer top lines of the outer cone of the large gear of the bevel gear pair in turn through the intermittent indexing of the milling cutter disk according to the cycloid. Li Jia et al. Proposed a spinning chamfering method and verified the feasibility of chamfering the tooth top of spiral bevel gear. Bian Bo et al. Proposed the chamfering method of spiral bevel gear based on conical cutter, which improved the chamfering accuracy. Wang et al designed the chamfering structure of conical grinding wheel, and studied the influence of grinding wheel structure size and installation position on the structure of conical sand head. Hu et al. Introduced a new method of robot gear chamfering with double edge chamfering. By designing the chamfering track of spiral bevel gear, chamfering both sides of two adjacent teeth at the same time.
At present, the chamfering of spiral bevel gear is a research hotspot. Disc tools are generally used to indirectly divide and cut the chamfering one by one for chamfering. The chamfering tool taking spiral bevel gear as the research object is not suitable for chamfering of cylindrical gear.
Foreign companies have designed chamfering tools and hobs on the same spindle, which realizes the combination of hobbing process and chamfering process, and saves the investment of special chamfering machine equipment. However, at present, the technology is blocked in China. Domestic users can customize special chamfering tools, but the price is expensive and the customization cycle is long. In order to meet the needs of high-efficiency tooth profile chamfering of cylindrical gears, a calculation method of rake face profile of hobbing chamfering tool is proposed, which provides a theoretical basis for forming an efficient “rough hobbing chamfering fine hobbing” compound machining process of gears.